M1917 strange front sight

[browningautorifle]

I must set the rear sight at 600 yards to be able to hit an 8 in.target at 100 m

That's what I was asking, so you need a shorter front sight...if that one's going anyway, keep taking the top off until it's correct and then measure for height. Then you know which one is required. There is a math formula, someone will probably bring it up. It would have been zeroed for a specific ammo by a target shooter, that's the types that would file it narrow. If you shoot M2 ball, you get the original velocity and group.

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[donki1967]

The problem is that...I have used LC M2 Ammo for testing this 1917.
To all members, which front sight height do you have on your rifle?and what is the correct rear sight position for you to hit your target at 100 m?
regards

[Patrick Chadwick]

... It would have been zeroed for a specific ammo by a target shooter, that's the types that would file it narrow. If you shoot M2 ball, you get the original velocity and group.

I don't think so. That blade is so extremely tall that no ammo is going to match the 100 backsight setting at 100 yards. It would need a trajectory that curves upwards. I think Bubba built up the blade, never got around to adjusting it, and passed the rifle on... or deliberately wanted to use the higher notches on the backsight.

[emmagee1917]

Your job is easy then . As was said , you need a shorter sight . Set your rear sight to where you WANT it to set when shooting . Measure the distance from a point on your sliding bar to a fixed point ( say , top of slide to bottom of the top crossbar ) . Now , set the sight to where you HAVE to set it to hit where you want . Remeasure and subtract one from the other . The difference is the amount you need to take off the front blade .
Chris

[donki1967]

Your job is easy then . As was said , you need a shorter sight . Set your rear sight to where you WANT it to set when shooting . Measure the distance from a point on your sliding bar to a fixed point ( say , top of slide to bottom of the top crossbar ) . Now , set the sight to where you HAVE to set it to hit where you want . Remeasure and subtract one from the other . The difference is the amount you need to take off the front blade .
Chris

Your method seems to be a good one, I will try this weekend and inform you.
Thanks

[browningautorifle]

Like I said, a mathematic solution...there we go.

[Patrick Chadwick]

"To all members, which front sight height do you have on your rifle?and what is the correct rear sight position for you to hit your target at 100 m?"

"The overall measure gives a height of 0.49 inch (blade=0.28 and the base=0.21), so I'm far from 060 or 090..."

I am surprised that no-one mentioned that the foresight blade is ridiculously tall. It has been fudged. Take a very close look with an eyeglass.

I just measured "Eddie", an (as far as I can tell) 100% original M1917 from Dec. 1918. Very low mileage indeed. Eddie fires pretty close to POA at 100 meters. That means, using a 6 o'clock hold on an 8" black it has to be set a bit higher to hit dead center. At the present it is set to 450 for 300 meter shooting, and needs (if I recall correctly) a 200 setting for 100 meters. All depending on the ammo, phases of the moon etc.
The foresight blade is marked .075. And 0.075" is the thickness of the base of the foresight blade, NOT the height of the blade itself. The blade is about 0.150 high, i.e. total height = 0.225". I measured without taking the sight apart, something which I have no intention of doing!

One would expect the 0.90 foresight to have EITHER a base that was 0.015" thicker (=0.90") OR a blade that was 0.015" taller (= 0.165") to give a total height of 0.250". Your foresight is way oversize, regardless of which way it is measured.

I can't tell from here, but it looks as if that foresight blade has been built up or replaced. So you are not spoiling a pristine original if you simply file it back down to a plausible size, as suggested by chris (emmagee1917).

BTW, since the correct setting is ammo-dependent, do not try to file it down for a perfect "fit" at 100 with the 100 setting. That only makes sense if you can guarantee that the rifle is going to be using precisely the same ammo with the same aim for ever! Not very probable. It would make zeroing impossible if you use a milder load. A 200 sight setting for a 100 distance gives you some leeway!

So follow Chris's method, but do not file it down the whole amount in one go. Leave about 0.060" reserve and test fire again. If you now need a 150 or 200 backsight setting for a 100 target, leave it alone.

[donki1967]

Patrick, even if I would copy your foresight mounting, it would be currently impossible.I found no retailer here in France or Germany who offers an .075 marked blade.
That's curious, I only find original blades from 0 to .045. The .075 does exist in their catalog, but is out of stock.
So you gave me your sighting configuration, any other mounting by members?

[browningautorifle]

Could be...

[M94/14]

The BLADE height of all the sight inserts as used on the M1917 and P14 are the same. They varied the height of the BASE portion of the sight insert to compensate for elevation zeroing variances. That is why the sight inserts have numbers on the base portion of them.